Carbon fiber composite level and method of manufacturing same

ABSTRACT

A composite level and a method to manufacture the composite level are provided. A composite level can have three layers of material. A first layer comprises a glass-mat material, a second layer comprises carbon fiber, and a third layer comprises a glass fabric material. A composite level can also have only two layers of material. At least one bubble vial is mounted on the level body. The method to manufacture the carbon fiber composite level comprises a pultrusion process wherein a fiber glass material and carbon fiber are saturated with resin and molded into a final shape.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application No.61/980,387, filed on Apr. 16, 2014, entitled “Carbon Fiber CompositeLevel and Method of Manufacturing Same.” The content of this applicationis incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to levels and more particularly tocomposite levels and methods for manufacturing the same.

BACKGROUND OF THE INVENTION

Levels are normally used in the construction or home improvementindustry to determine an angular orientation of a surface against whichthe level is placed or aligned. Levels of various sizes and shapes areavailable and are typically manufactured using an aluminum extrusion andfiber glass molding process. It is desirable for a level to be strongand durable, yet light weight and easy to handle. The present inventionprovides an improvement in the level and in the method of manufacturingthe same.

SUMMARY OF THE INVENTION

One aspect of the present patent application provides a level made froma carbon fiber composite material. In one embodiment, the levelcomprises a level body having a fiber glass layer and a carbon fiberlayer. At least one bubble vial is mounted on the level body. The fiberglass layer may comprise a glass-mat material or a glass fabricmaterial. The carbon fiber layer may be present in an amount frombetween 10% to 90% by volume in the level body. In one embodiment, thelevel body comprises between about 12%-15% by volume the carbon fiberlayer.

In another embodiment, the level body comprises two fiber glass layersand a carbon fiber layer. One fiber glass layer may comprise a glass-matmaterial and a second fiber glass layer may comprise a glass fabriclayer. The carbon fiber layer may be disposed between the two fiberglass layers.

In yet another embodiment, the level includes an internal supportstructure, the level body may have a generally tubular configurationincluding a top wall and a bottom wall generally parallel to oneanother, and a pair of spaced side walls; a top opening in the levelbody that interrupts at least a portion of the top wall to accommodatethe at least one bubble vial; and an internal support structure disposedwithin the tubular configuration of the body and spanning longitudinallyalong the body so as to be disposed on both sides of the top opening toprovide structural support to the body in the vicinity of the topopening. The internal support structure may comprise high impact ABS.

Another aspect of the present patent application provides a method tomanufacture a level. In one embodiment, the method comprises forming alevel body through a pultrusion process wherein the level body comprisesa fiber glass layer and a carbon fiber layer and mounting at least onebubble vial on the level body. The pultrusion process comprisessaturating fiber glass and carbon fiber with resin and pressing thefiber glass/resin material and carbon fiber/resin material into a shapefor the level body. The fiber glass layer may comprise a glass-matmaterial or a glass fabric material. The carbon fiber layer may bepresent in an amount from between 10% to 90% by volume in the levelbody. In one embodiment, the level body comprises between about 12%-15%by volume the carbon fiber layer.

In another embodiment, the method comprises forming a level body havingtwo fiber glass layers and a carbon fiber layer. One fiber glass layermay comprise a glass-mat material and a second fiber glass layer maycomprise a glass fabric layer. The carbon fiber layer may be disposedbetween the two fiber glass layers.

In yet another embodiment, the method comprises providing an internalsupport structure disposed within the level body. The method comprisesforming the level body into a generally tubular configuration includinga top wall and a bottom wall generally parallel to one another, and apair of spaced side walls. The method further comprises cutting a topopening in the level body that interrupts at least a portion of the topwall to accommodate the at least one bubble vial. The method furthercomprises providing an internal support structure disposed within thetubular configuration of the body and spanning longitudinally along thebody so as to be disposed on both sides of the top opening to providestructural support to the body in the vicinity of the top opening.

These and other aspects of the present patent application, as well asthe methods of operation and functions of the related elements ofstructure and the combination of parts and economies of manufacture,will become more apparent upon consideration of the followingdescription and the appended claims with reference to the accompanyingdrawings, all of which form a part of this specification, wherein likereference numerals designate corresponding parts in the various figures.In one embodiment of the present patent application, the structuralcomponents illustrated herein are drawn to scale. It is to be expresslyunderstood, however, that the drawings are for the purpose ofillustration and description only and are not intended as a definitionof the limits of the present patent application. It shall also beappreciated that the features of one embodiment disclosed herein can beused in other embodiments disclosed herein. As used in the specificationand in the claims, the singular form of “a”, “an”, and “the” includeplural referents unless the context clearly dictates otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a level according to an embodiment ofthe invention;

FIG. 1B is a side view of the level shown in FIG. 1A;

FIG. 1C is a side view of the opposite side of the level shown in FIG.1B;

FIG. 1D is an end view of the level shown in FIG. 1A;

FIGS. 2A-B are an end view (with end cap removed) and a cross-sectionalview (taken through the line A-A′ in FIG. 1A), respectively;

FIG. 3 is an exploded view of a level according to an embodiment of theinvention;

FIG. 4A is a perspective view of a vial assembly according to anembodiment of the invention;

FIG. 4B is a side view of the vial assembly shown in FIG. 4A;

FIG. 4C is a side view of the opposite side of the vial assembly shownin FIG. 4B;

FIG. 4D is an end view of the vial assembly shown in FIG. 4A;

FIG. 4E is an exploded view of the vial assembly shown in FIG. 4A;

FIG. 5A is a perspective view of a vial cover used in a vial assemblyaccording to an embodiment of the invention;

FIG. 5B is a side view of the vial cover shown in FIG. 5A;

FIG. 5C is a side view of the opposite side of the vial cover shown inFIG. 5B;

FIG. 5D is an end view of the vial cover shown in FIG. 5A;

FIG. 5E is an exploded view of the vial cover shown in FIG. 5A;

FIG. 6A is a perspective view of a vial assembly according to anembodiment of the invention;

FIG. 6B is a side view of the vial assembly shown in FIG. 6A;

FIG. 6C is a side view of the opposite side of the vial assembly shownin FIG. 6B;

FIG. 6D is an end view of the vial assembly shown in FIG. 6A;

FIG. 6E is an exploded view of the vial assembly shown in FIG. 6A;

FIG. 7A is a cross sectional view of an eyelet assembly according to anembodiment of the invention;

FIG. 7B is a top view of the eyelet assembly shown in FIG. 7A;

FIG. 7C is a side view of the eyelet assembly shown in FIG. 7A;

FIG. 8A is a side view of the level of FIG. 1A, with the level bodyshown in dashed lines to better review various components mountedthereto according to an embodiment of the invention; and

FIG. 8B is a top view of the various components shown in FIG. 8A, withthe level body shown in dashed lines; and

FIG. 8C is a side view of the opposite side of the various componentsshown in FIG. 8A, with the level body shown in dashed lines.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT(S)

Referring now more particularly to the drawings, FIGS. 1A-D show thegeneral layout of a level 10 according to an embodiment of theinvention. The level 10 has an elongated body 11 that comprises an upperwall 12 and a lower wall 14 that is generally parallel to the upper wall12. A first side wall 16 is generally perpendicular to the upper 12 andlower 14 walls, and a second side wall 18 is also generallyperpendicular to the upper 12 and lower 14 walls. The sidewalls 16 and18 are spaced from one another and generally parallel to one another.Each of the walls 12, 14, 16, and 18 generally extend longitudinallyfrom end to end of the body 11 of the level 10, although they may bediscontinuous in certain areas to accommodate various components mountedto the body. End cap 32 may be secured using eyelet assembly 33 at theends of the body 11 for protection against impact and/or ease of use.The end cap 32 may be made of rubber, plastic, elastomer, wood, metal,or any other suitable material. As will be discussed in greater detailbelow, in one embodiment, level body 11 is made of a carbon fibercomposite material and formed through a pultrusion process.

In one embodiment, the level 10 may be formed to a shape in accordancewith the teachings of U.S. Pat. No. 7,484,307 (“the '307 patent”),hereby incorporated by reference. As shown in FIGS. 1A-D, the upper wall12 has a top opening 24 therethrough at a generally central location,though it will be appreciated that the opening 24 may be at alternatelocations along the upper wall 12. In one embodiment, as shown in theFIGS., the upper wall 12 can be provided with a first linear edge 20that extends uninterruptedly from end to end of the body 11, while asecond linear edge 22 is interrupted at the opening 24, as disclosed inthe '307 patent. However, the present invention is not limited to suchconfiguration and can include a top center vial that entirely disruptsthe upper wall 12, just for example. As shown in the illustratedembodiment, the first linear edge 20 is disposed at an operativeconnection of the upper wall 12 and the second side wall 18. The secondlinear edge 22 is disposed at the operative connection between the upperwall 12 and the first side wall 16.

As shown, the first side wall 16 may have a side opening 26 that iscontiguous with the top opening 24 in the upper wall 12. A bubble vial28 is carried in a vial assembly 60 and installed in a cavity formed bythe openings 24, 26 such that it may be used for leveling purposes. Thebubble vial 28 may therefore be visible from a first direction, throughthe top opening 24 in the upper wall 12, and from a second directionorthogonal to the first, through the side opening 26 in the first sidewall 16. In this manner, a level 10 is described that has anuninterrupted marking surface (edge 20) and a bubble vial 28 that isvisible from at least two orthogonal directions.

In addition, in the illustrated embodiment, because the top opening 24is contiguous with side opening 26, the bubble vial 28 can be viewedfrom a wide range of angles, without disruption. That is, the bubblevial 28 can be viewed through the top of the vial body (i.e., throughtop opening 24), and continuously through angles extending to the sideopening 26 and beyond, so that the vial can be viewed at angles along anarc of at least 120° without any intervening opaque structure, such asan edge surface of the body.

As shown, a second side opening 30 is provided through the second sidewall 18. The opening 30 in the second side wall 18 allows the bubblevial 28 to be visible from a third direction that is orthogonal to thefirst direction and opposite to the second direction, described above.

Turning to FIG. 2A, an end view of level 10 with end cap 32 removed isshown. As shown, the level 10 may have a generally I-shaped box-beamtype structure of the type described in the aforementioned U.S. Pat. No.7,484,307. The first side wall 16 may have a first upper wall flangeportion 34 that intersects with the upper wall 12, a first lower wallflange portion 36 that intersects with the lower wall 14, and a firstmain wall portion 38 extending between the first upper wall flangeportion 34 and the first lower wall flange portion 36.

The second side wall 18 may similarly have a second upper wall flangeportion 40 that intersects with the upper wall 12, a second lower wallflange portion 42 that intersects with the lower wall 14, and a secondmain wall portion 44 extending between the second upper wall flangeportion 40 and the second lower wall flange portion 42.

As shown, the first main wall portion 38 is generally parallel to thesecond main wall portion 44. One of skill in the art will appreciatethat the present invention is not limited to each of the main wallportions 38, 44 being parallel to each other. For example, the main wallportions 38, 44 may form a V-shaped cross-section with the distancebetween them being smaller at a region closer to the lower wall 14 thanthe distance between them at a region closer to the upper wall 12, orthe main wall portions 38, 44 may form an inverted V-shapedcross-section. Moreover, the main wall portions 38, 44 may be curved orirregularly shaped such that any desirable cross-section may beachieved, such as a concave, convex, or ribbed configuration.

As shown, the first upper wall flange portion 34 is generally parallelto the second upper wall flange portion 40, and the first lower wallflange portion 36 is generally parallel to the second lower wall flangeportion 42. One of ordinary skill in the art will appreciate thatvariations on the orientation of the wall flange portions may be madewithin the scope of the present invention.

The first side wall 16 may further comprise a first upper angled wallportion 46 and a first lower angled wall portion 48. The first upperangled wall portion 46 connects the first main wall portion 38 with thefirst upper wall flange portion 34 and the first lower angled wallportion 48 connects the first main wall portion 38 with the first lowerwall flange portion 36. The second side wall 18 may likewise comprise asecond upper angled wall portion 50 and a second lower angled wallportion 52. The second upper angled wall portion 50 connects the secondmain wall portion 44 with the second upper wall flange portion 40 andthe second lower angled wall portion 52 connects the second main wallportion 44 with the second lower wall flange portion 42.

In one embodiment, the first 46 and second 50 upper angled wall portionsand the first 48 and second 52 lower angled wall portions form angles of90 degrees with respect to the first 38 and second 44 main wallportions. One skilled in the art will appreciate that the angled wallportions 46, 50, 48, 52, may form an angle with respect to the main wallportions 38, 44 in the range of greater than about 0 degrees to lessthan about 180 degrees.

In one embodiment, the level body 11 has a more traditional “box-beam”shape. In another embodiment, the level may be formed to a shape inaccordance with the teachings of U.S. Pat. No. 6,675,490, herebyincorporated by reference, wherein the level has a generally I-shapedbox-beam type structure similar to the structure described above, withone difference being the opening in the first side wall is notcontiguous with the opening in the top wall. In yet another embodiment,the level may be formed to a shape in accordance with the teachings ofU.S. Pat. App. Pub. 2013/0192075, hereby incorporated by reference,wherein the level body has a generally I-beam configuration.

Turning back to FIGS. 1A-D, the bubble vial 28 has a fixed calibratedorientation with respect to the lower wall 14. In the embodiment shown,the bubble vial 28 is oriented such that its longitudinal axis issubstantially parallel to the lower wall 14. Accordingly, the lower wall14 may be placed upon a horizontal surface and the bubble vial 28 may bereferred to in order to determine whether the surface is level. Thebubble 28 may also have a fixed calibrated orientation with respect tothe top wall 12, so that the top wall 12 can be placed on a horizontalsurface and the bubble vial 28 may be referred to in order to determineif the surface is level. As will be described in greater detail below,bubble vial 28 is secured in the level using a vial assembly 60.

Level 10 may include additional openings for other bubble vials. In oneembodiment, vial assemblies 70 and 72 are secured into openings that maybe provided through each of the main walls 38, 44 at locations within oron the body 11 of the level 10. In one embodiment, a bubble vial thathas a longitudinal axis perpendicular to the lower wall may be providedin vial assembly 70 for a plumb determination. In this embodiment, thelower wall 14 or upper wall 12 may be placed against a vertical surface,and the bubble vial may be referred to in order to determine whether thevertical surface is plumb.

A further bubble vial may be provided at another location within or onthe level body 10, such as vial assembly 72, in order to determinewhether a surface is oriented at 45 degrees. For this purpose, thebubble vial may have a fixed orientation at 45 degrees with respect tothe lower wall 14 and/or upper wall 12, so that such a determination maybe made by placing the upper 12 or lower 14 wall against the surfacebeing tested. One of ordinary skill in the art will appreciate that abubble vial of any angular orientation with respect to the lower wall 14may be installed in a level 10 in accordance with the present inventionwithout departing from its scope. Moreover, a bubble vial may beprovided that has a variable orientation such that a user may orient thevial at an angle suitable for a particular application and later changeits angle as the situation requires.

Turning to FIG. 2B, a cross-sectional view of level 10 taken along lineA-A′ in FIG. 1A shown. As shown, level body 11 has a three layerconstruction with an inner layer 97, middle layer 98, and outer layer99. In one embodiment, level body 11 is made through pultrusionprocesses. Generally the pultrusion process involves first saturating afiber material, such as fiber glass or carbon fiber, with a suitableresin. The resin may be a thermosetting or thermoplastic resin. In oneembodiment, the resin is unsaturated polyester. The saturation processmay be through various methods such as spraying, dipping, injecting,roll coating, or other comparable methods. After saturation of the fibermaterials with the resin, the fiber/resin material is pulled into a diethat shapes and cures the material into the shape of the desiredpultruded article. The pultruded article may then cut to the appropriatesize and further processed into the final product.

In one embodiment, inner layer 97 may include glass-mat, middle layer 98may include carbon fiber 98, and outer layer 99 may include glassfabric. Glass-mat may be a sheet of nonwoven fiber glass filaments.Glass fabric may be a sheet of woven fiber glass filaments. Inner layer97 and outer layer 99 may be other suitable fiber glass materials.

In one embodiment, the manufacturing process for a level body 11 is asfollows. The fiber glass materials (glass-mat and glass fabric) andcarbon fiber are first saturated with a resin such as unsaturatedpolyester. The resin saturated glass-mat, carbon fiber, and glass fabricmaterial are fed into a die such that the glass-mat/resin material formsan inner layer, the carbon fiber/resin material forms a middle layer,and the glass fabric/resin material an outer layer. The die then moldsthe three layers into the desired shape, such as the generally I-shapedbox beam described above, and cures the layers. The pultruded level bodymay be cut to the appropriate size to make levels of different sizes,such as 24″, 48″, 72″, 78″, and 96″ levels. The level body may befurther processed, such as cutting out openings for various inserts andother processing steps to form the final product.

In one embodiment, level body 11 may be made with two layers instead ofthree, specifically a fiber glass layer and a carbon fiber layer. Theprocess for making a two layer level body is substantially the same asdescribed above, except with only one fiber glass layer.

The amount of each material in each layer of the level body 11 may bevaried. The carbon fiber layer 98 in the level body 11 may be from 10%to 99% by volume and the fiber glass layers 97, 99 combined may be from1% to 90% by volume. Level body 11 may comprise 50% by volume fiberglass layers combined and 50% by volume carbon fiber layer, 60% byvolume fiber glass layers combined and 40% by volume carbon fiber layer,70% by volume fiber glass layers combined and 30% by volume carbon fiberlayers, 80% by volume fiber glass layers combined and 20% by volumecarbon fiber layer, or 90% by volume fiber glass layers combined and 10%by volume carbon fiber layer. In one embodiment, level body 11 comprises85% by volume of the fiber glass layers 97, 99 combined and 15% byvolume carbon fiber layer 98.

The amount of fiber glass materials (glass-mat and glass fabric) andcarbon fiber may be varied based on need and in an amount that wouldstill produce a level body 11 of suitable strength. While carbon fiberis stronger and lighter than the fiber glass materials, carbon fiber isalso costlier. Consideration of factors such as strength, weight, andcost may aid in determining the amount of each material to be used inlevel body 11. The outer layer may also be chosen for suitability offurther processing, such as painting, of the level body 11 to make thefinal level 10 product.

Applicants have found that manufacturing the level body 11 using thematerials and methods described above provides a level 10 of sufficientstrength, but at the same time, is lighter than comparable conventionallevels made from other material, such as aluminum. In one embodiment, a48″ level made with a carbon fiber composite according to the methoddescribed above may be over 30% lighter than a comparable 48″ level madewith aluminum.

Turning to FIG. 3, an exploded view of a level 10 according to anembodiment of the invention is shown. Various openings may be cut intolevel body 11 to accommodate different components. In one embodiment,openings may be cut at a generally central location to house ahorizontal level indicating vial assembly at that location within levelbody 11. The upper wall 12 of level body 11 has an opening 24 that iscontiguous with a side opening 26 in the first side wall 16. The secondside wall 18 has a side opening 30 that is not contiguous with the topopening 24 in the upper wall. Other suitable openings may be cut intolevel body 11 to accommodate the horizontal level indicating vialassembly, for example where opening 24 is not contiguous with sideopening 26.

Substantially square openings 76 may be cut through both side walls 16,18 to accommodate vial assemblies. Circular openings 74 cut through bothside walls 16, 18 may be used by eyelet pieces 35, 37 to secure end caps32. Other shapes and sizes for openings 74, 76 may be used.

Turning to FIGS. 4A-E, various views of a horizontal level indicatingvial assembly 60 according to an embodiment are shown. Vial assembly 60is constructed and arranged to secure a horizontal level indicatingbubble vial 28 in an operative position. Vial assembly 60 includes vialcarrier base 61, vial carrier 62, pad 63, vial cover pieces 65, 67,bubble vial 28, and screws 64. As discussed in greater detail below,when secured in an operative position inside level body 11, vialassembly 60 provides additional strength to the level 10.

In the embodiment shown, vial carrier base 61 is a substantiallyU-shaped piece. Vial carrier base 61 may be produced as a one piececomponent molded from a suitable plastic material, for example, highimpact ABS. Other suitable material may be used, such as metal, to makevial carrier base 61. In one embodiment, the walls of vial carrier baseinclude grooves 68, 69. Grooves 68, 69 in vial carrier base 61 providevoids or pockets wherein adhesives, such as epoxy adhesive, may bedeposited. The grooves 68, 69 are filled with adhesive to secure vialassembly 60 in an operative position inside level body 11.

As shown, vial carrier base 61 includes several grooves 68, 69 ofdifferent shapes and sizes and at various locations. Grooves 69 on theupward extending legs of the U-shaped vial carrier base 61 may be formedin an irregular pattern. Grooves 69 may include large grooves withvarious smaller channels or grooves branching off the large grooves tofacilitate in the attachment with the adhesive to the level body 11.Additional grooves such as grooves 68 may be formed on the lower baseportion of the vial carrier base 61. The grooves 68 shown aresubstantially straight vertical cutouts on the base of the vial carrierbase 61. Grooves 68, 69 are formed on both the front side and back sideof the vial carrier base 61. Other suitably shaped, sized, and locatedgrooves may be formed in vial carrier base 61. For example, deepergrooves may be used to contain a greater amount of adhesive. Grooves maybe formed as part of the molding process in making the vial carrier base61 or material may be cut out of the vial carrier base 61 to form thegrooves.

Vial carrier 62 may be formed to fit into the inner portion of theU-shaped configuration of the vial carrier base 61. Vial carrier 62 mayhave snap action elements disposed on the bottom surface that securesonto vial carrier base 61. Vial carrier 62 may include groove 66 similarto grooves 68, 69 in vial carrier base 61. Groove 64 provide a void orpocket to contain adhesive. As discussed with grooves 68, 69, groove 64may be formed with various shapes, sizes, and locations. For example, asshown, groove 64 comprises various small channels or grooves tofacilitate in the attachment with the adhesive to the level body 11.Vial carrier 62 may be produced as a one piece component molded from asuitable plastic material, for example, high impact ABS. Other suitablematerial may be used, such as metal, to make vial carrier 62.

Bubble vial 28 may be secured onto vial carrier 62 with screws 64 orother suitable fixation devices. Screws 64 may be made of plastic,metal, or other suitable material. Pad 62 may be placed between bubblevial 28 and vial carrier 62 to cushion bubble vial 28. Pad 26 may be anysuitably soft material, such as rubber. In one embodiment, pad 62 may beomitted.

In one embodiment, bubble vial 28 comprises a barrel shaped openingformed in a solid rectangular block of clear plastic material. Inanother embodiment, bubble vial 28 may have a rounded top surface (acylindrical upper portion and rectangular block lower portion) inaccordance with the teachings of U.S. Pat. No. 7,464,479, herebyincorporated by reference. In one embodiment, bubble vial 28 may be madein accordance with the teachings of U.S. patent application Ser. No.14/107,908, filed Dec. 16, 2013, hereby incorporated by reference. It iscontemplated that any type of level indicating vial may be used that iscapable of providing accurate horizontal level indications.

FIGS. 5A-E show various views of a vial cover 69 comprising vial coverpieces 65, 67. Vial cover 69 may include a dove tail feature in the malevial cover piece 65 and the female vial cover piece 67. The dove tailfeature allows the vial cover pieces 65, 67 to be aligned vertically andhorizontally with respect to each other when fixed into place overbubble vial 28. Vial cover pieces 65, 67 may also be molded from asuitable plastic material, for example, high impact ABS. Other suitablematerial may be used, such as metal, to make vial cover pieces 65, 67.

FIGS. 6A-E show various views of vial assembly 80 according to anembodiment of the invention. In one embodiment, vial assembly 80 may bevial assemblies 70 and 72 shown in FIGS. 1A-D. Vial assembly 80 may beused for plumb determination or for determining whether a surface isoriented at 45 degrees (or any other suitable degree). A pair ofsubstantially square cover pieces 81, 82 retains bubble vial 83 in anoperative position between walls 16, 18 of level 10. The pair of coverpieces 81, 82 are moved axially toward one another within opening 76into an operative position. Screws 84 secure cover pieces 81, 82. Coverpieces 81, 82 may be molded from a suitable plastic material, forexample, high impact ABS. Other suitable material may be used, such asmetal, to make cover pieces 81, 82.

In one embodiment, bubble vial 28 may be made in accordance with theteachings of U.S. patent application Ser. No. 14/107,908, filed Dec. 16,2013, hereby incorporated by reference. It is contemplated that any typeof level indicating vial may be used that is capable of providingaccurate level indications.

FIGS. 7A-C show various views of eyelet assembly 33 according to anembodiment of the invention. Eyelet assembly 33 may be used to secureend caps 32 through openings 74. Eyelet assembly 33 includes male eyeletpiece 35 and female eyelet piece 37. Piece 35 secures onto piece 37through an annular snap fit technique. Eyelet pieces 35, 37 may bemolded from a suitable plastic material, for example, high impact ABS.Other suitable material may be used, such as metal, to make eyelet piece35, 37.

FIGS. 8A-C show various components in level 10. Level body 11 is shownwith dashed lines. As shown in FIG. 8A, vial carrier base 61 is widerthan openings 24, 26. Vial carrier base 61 may be inserted into levelbody 10 by first sliding one leg of the U-shaped vial carrier base 61through openings 24, 26 and then pushing the remaining portions of thevial carrier base 61 into the openings 24, 26. Alternatively, vialcarrier base 61 may be slid into level body 11 through the ends andpushed into the center of level body 11. After vial carrier base 61 ispositioned in level body 11, adhesive, for example epoxy adhesive, isapplied to the vial carrier base 61 at grooves 64, 68, 69 to fix thecarrier base 61 inside the level body 11. In one embodiment, the epoxyadhesive is SCOTCH-WELD Epoxy Adhesive 2216 B/A from 3M. Once theadhesive is set or cured, the remaining pieces of horizontal levelindicating assembly 60 may be secured onto the vial carrier base 61.Vial carrier 62, pad 63, and bubble vial 28 are screwed onto vialcarrier base 61 and vial cover pieces 65, 67 are snapped togetherthrough openings 26, 30.

Applicants have found that vial assembly 60 provides additional strengthto a level 10 produced using the materials and methods described above.In particular, vial carrier base 61 acts an internal support structure.

Prior to cutting openings 24, 26, 30 in level body 11, the carbon fibermaterial run along the whole length of the level body 11 as continuousstrands of fiber material and the fiber glass materials are a continuoussheet of glass fiber. Cutting openings 24, 26, 30 cause breaks in thecarbon fiber material and the fiber glass materials, which weaken thelevel body 11. The openings 24, 26, 30 further produce stress points atthe corners of the openings in level body 11. When installed in itsoperative position, vial assembly 60 provides support to level body 11.

As shown, vial assembly 60, and in particular vial carrier base 61 spansthe width of openings 24, 26. When seated inside level body 11, the topside of the two legs in the U-shaped portion of vial carrier base 61abuts the inside surface of the top wall 12 of level body 11 immediatelybeyond the opening 24 on the top wall 12. The bottom side of thelongitudinal portion of vial carrier base abuts the inside surface ofthe bottom wall 14 of level body 11. The vial carrier base 61 is madewith a thickness that is substantially the size of the space spanningthe inner surface of side walls 16, 18 so that the front side and backside of vial carrier base 11 abuts the inner surface of side walls 16,18. In this configuration, vial carrier base 61 provides additionalsupport to the weakened portions of level body 11 at the corners whereopenings 24, 26, 30 are cut.

In the embodiment shown, the width of vial carrier base 61 isapproximately twice the width of openings 24, 26 and the inside width ofthe U-shaped portion is approximately the width of openings 24, 26. Asshown, openings 24, 26 are 56.2 mm wide and vial carrier base 61 is 120mm wide. In one embodiment, vial carrier base is 120 mm wide, 58 mmhigh, 15 mm thick, and the distance between the two upstanding legs is57 mm. The size of vial carrier base 61 may be varied depending on need.

Additional support may be provided by the adhesive used to secure vialassembly 60 inside level body 11. Adhesive may be dispensed into grooves64, 68, 69 and any other voids between vial assembly 60 and the insidewalls of level body 11. Once hardened or cured, the adhesive secures thevial assembly 60 and further solidifies level body 11. Any suitableadhesive may be used. An epoxy adhesive having a modified epoxy base anda modified amine accelerator may be used. In one embodiment, the epoxyadhesive is SCOTCH-WELD Epoxy Adhesive 2216 B/A from 3M.

In one embodiment, the level 10 is capable of withstanding a load testof a 200 pound load at the center of the level while the ends aresupported on a platform without damage. The level 10 is capable ofwithstanding the load test on all four surfaces of the level. The levelis also capable of withstanding a torsion test of twisting the ends ofthe level without damage.

Although the present patent application has been described in detail forthe purpose of illustration, it is to be understood that such detail issolely for that purpose and that the present patent application is notlimited to the disclosed embodiments, but, on the contrary, is intendedto cover modifications and equivalent arrangements that are within thespirit and scope of the appended claims. In addition, it is to beunderstood that the present patent application contemplates that, to theextent possible, one or more features of any embodiment can be combinedwith one or more features of any other embodiment.

What is claimed is:
 1. A level comprising: a level body comprising alayer of fiber glass material and a layer of carbon fiber material, thefiber glass material layer being positioned adjacent the carbon fibermaterial layer; and at least one bubble vial mounted on the level body.2. The level of claim 1, wherein the fiber glass material layercomprises a glass-mat material.
 3. The level of claim 1, wherein thefiber glass material layer comprises a glass fabric material.
 4. Thelevel of claim 2, wherein the level body comprises a second fiber glassmaterial layer comprising a glass fabric material.
 5. The level of claim4, wherein the carbon fiber material layer is disposed between theglass-mat material layer and the glass fabric material layer.
 6. Thelevel of claim 1, wherein the level body has a generally tubularconfiguration including a top wall and a bottom wall generally parallelto one another, and a pair of spaced side walls generally perpendicularto the top and bottom walls; a top opening in the level body thatinterrupts at least a portion of the top wall to accommodate the atleast one bubble vial; and an internal support structure disposed withinthe tubular configuration of the body and spanning longitudinally alongthe body so as to be disposed on both sides of the top opening toprovide structural support to the body in the vicinity of the topopening.
 7. The level of claim 6, wherein the internal support structurecomprises high impact ABS material.
 8. The level of claim 6, wherein theat least one bubble vial is mounted on the internal support structure.9. The level of claim 1, wherein the level body comprises between about10% and about 90% by volume of the carbon fiber material layer.
 10. Thelevel of claim 1, wherein the level body comprises between about 12% andabout 15% by volume of the carbon fiber material layer.
 11. A method formanufacturing a level comprising: forming a level body through apultrusion process, wherein the level body comprises a layer of fiberglass material and a layer of carbon fiber material, the fiber glassmaterial layer being positioned adjacent the carbon fiber materiallayer; and mounting at least one bubble vial on the level body.
 12. Themethod of claim 11, wherein the pultrusion process comprises saturatinga fiber glass material and a carbon fiber material with a resin andpressing the fiber glass/resin material and carbon fiber/resin materialinto a shape for the level body.
 13. The method of claim 11, wherein thefiber glass material layer comprises a glass-mat material.
 14. Themethod of claim 11, wherein the fiber glass material layer comprises aglass fabric material.
 15. The method of claim 13, wherein the levelbody comprises a second fiber glass material layer comprising a glassfabric material.
 16. The method of claim 11, wherein the level body isformed into a generally tubular configuration including a top wall and abottom wall generally parallel to one another, and a pair of spaced sidewalls generally perpendicular to the top and bottom walls.
 17. Themethod of claim 16, further comprising cutting a top opening in thelevel body that interrupts at least a portion of the top wall toaccommodate the at least one bubble vial.
 18. The method of claim 17,further comprising providing an internal support structure disposedwithin the tubular configuration of the body and spanning longitudinallyalong the body so as to be disposed on both sides of the top opening toprovide structural support to the body in the vicinity of the topopening.
 19. The method of claim 11, wherein the level body comprisesbetween about 10% and about 90% by volume of the carbon fiber materiallayer.
 20. The method of claim 11, wherein the level body comprisesbetween about 12% and about 15% by volume of the carbon fiber materiallayer.